Beitou is famous of hot spring. And the name is from the Pingpu language, which means “witch”. Due to the hot spring sulfur vapors from all over the Beitou area, the place is always misty. The local aborigines believe that the mist here is because there are witches casting spells in the mountain, so the place is named the land of witches. This EarthCache will bring you to get closer to the witch's cauldron and taste the “delicacies” cooked by it.
作為溫泉鄉聞名的北投，其地名是源於平埔族語的女巫之意，由於北投地區各處冒出的溫泉硫磺蒸氣使得這個地方終年雲霧飄渺，也為這個地方蓋上了一層神秘的面紗。當地的原住民認為此處之所以雲霧飄渺是因為有女巫在山上施法，因此將此地命名為女巫之地。這個地質寶將帶大家近距離靠近女巫的大釜，並品嚐由其煮出的佳餚。
Attention!! All the food (knowledge) in this EarthCache is for your brain to taste (learn), please do not try to put anything into your mouth, in addition, due to the danger of high temperature in the kitchen (fumarole), please do not touch or approach!
注意！在本寶中所有的美食(知識)都是讓你的大腦品嚐(學習)，請不要試圖將任何東西放入你的口中，另外由於廚房(噴氣口)高溫危險，請不要隨意碰觸或靠近！
The Formation of Tatun Volcano Group / 大屯火山群的形成
Taiwan is located at the junction of the Philippine Sea plate and the Eurasian plate. The Philippine Sea plate continues to drill and squeeze under the Eurasian plate. When it reaches a depth of 150 km underground, the plate will be melted into magma by the high heat inside the earth. It called "plate subduction zone".
台灣位於菲律賓海板塊與歐亞大陸板塊的交接處，菲律賓海板塊不斷往歐亞大陸板塊底下鑽擠，當鑽到地下150公里深處時，板塊會被地球內部的高熱融化成岩漿。地質學家稱此處為"板塊隱沒帶"。
The magma rises up along the fault cracks, rushes to the surface, and forms a volcanic eruption. 2.8 million years ago, the Datun volcanic area was located in the subduction zone of the plate. With countless faults providing magma outlets, the volcanic eruption began for more than 2 million years. activity. Until 350,000 years ago, due to the push of the Philippine Sea plate, the Eurasian plate bent further down, causing the plate to submerge and migrate westward, interrupting the source of magma in the Datun volcanic area, and the eruption stopped. During this period of more than two million years of volcanic eruption, over 20 volcanoes were created, forming today's Tatun Volcano Group.
岩漿順著斷層裂縫往上冒，沖開地表，便形成火山爆發。280萬年前，大屯火山區處於板塊隱沒帶上，加上無數斷層提供岩漿出路，就這樣開始了持續200多萬年的火山爆發活動。一直到35萬年前，由於受菲律賓海板塊的推擠，歐亞大陸板塊更往下彎曲，促使板塊隱沒帶往西遷移，中斷大屯火山區的岩漿來源，於是爆發停止了。在這段長達兩百多萬年的火山爆發活動期間總共先後造出20餘座火山，形成了今天的大屯火山群。
The Formation of Fumarole / 噴氣口的形成
Longfenggu, Liuhuanggu, and Xiaoyoukeng are all explosion crater caused by post-volcanic action.
龍鳳谷與周邊的硫磺谷，還有更上方的小油坑都是屬於後火山作用造成的爆裂口。
After the volcanic activity ceases, there is still residual heat under the ground. This waste heat heats the remaining gas under the ground, increasing the pressure of the accumulated vapor under the ground. Finally, in certain specific places, such as volcanic craters or faults, the ground blasted out, resulting in explosion crater. There are often fumaroles, sulfur pores and hot springs in the rupture. Gas and heated groundwater may also rush out of the surface along faults and fissures, directly forming fumaroles , hot springs or geysers. These phenomena are called post-volcanic action.
火山活動終止之後，地底下仍然有殘留的熱能。這些餘熱加熱地底下殘留的氣體，使地底下累積之蒸氣壓力增大。最後在某些特定地點，如火山口或斷層附近爆破地面而出，造成爆裂口。在爆裂口內常有噴氣孔、硫氣孔和溫泉的存在。氣體及受熱地下水也有可能沿著斷層裂隙衝出地表，直接形成噴氣孔、溫泉或間歇泉。這些現象稱為後火山作用。
When the volcanic activity ceases, there is still a heat source in the ground. When rainwater flows into the stratum and becomes groundwater, it is steamed into water vapor by the heat source. This water vapor is ejected along the fault cracks, causing a large amount of vapor to be emitted.
當火山活動停止後，地底仍殘留熱源，當雨水流入地層中變成地下水後，被熱源蒸煮成水蒸氣，這些水蒸氣順著斷層裂縫噴冒出來，造成白煙縷縷的現象。而這樣的噴氣孔活動，就是被當地原住民當成有女巫在施法的真面目。
The Steamed and Colored Rock / 被上色與被蒸熟的石頭
Affected by the high-temperature steam and sulfur gas from the fumaroles, the minerals in the rock will be dissolved and then lost or surfaced. This phenomenon is called Alteration. Alteration: mineral alteration the changing of minerals and rock fabrics chemically by heat and fluid circulation.
受到噴氣孔的高溫蒸氣跟硫氣的影響，岩石中的礦物質會受到溶解，然後會流失或是浮現在表面。這種現象被稱為熱水換質作用 (或稱蝕變作用)。蝕變作用：指岩石、礦物受到熱液的影響，產生適合新的物理-化學條件下新的礦物或礦物組合的過程。
Because the fumaroles of Longfenggu contain a large amount of sulfur gas, they have strong corrosive power. Under the long-term steaming of high temperature and strong corrosive sulfur gas, the rocks near the fumaroles have undergone changes in color, hardness, and properties due to alteration. In this EarthCache, you can observe the fumarole at close range and actually feel the process of change.
由於龍鳳谷的噴氣含有大量的硫氣，具有極強的腐蝕力，在高溫和強蝕的硫氣長期蒸煮之下，在噴氣口附近的岩石因為蝕變作用而產生了顏色、硬度、性質上的轉變。在這個地質寶，你可以在近距離觀察噴氣口，並且實際感受這個變化的過程。
To log this cache, please answer the following questions:
- How would you like your rock to be cooked? / 你的石頭要幾分熟？
a. Pick up some rocks in similar size on the ground or on the wall at posted coordinates and waypoint 2.
在公布座標點和Waypoint 2的地上或是山壁上撿起大小相近石頭。
b. Please describe the difference (weight, color, or how it feels like) of the rocks in the two locations.
請形容一下兩個地點石頭的差異 (重量、顏色、觸感)。
c. Do you think they are the same kind of rocks? Please explain your answer.
請問你覺得他們是同一種石頭嗎？ 請解釋你的答案。
d. In your opinions, which place’s rock is "cooked"? Please explain your answer.
請問你覺得哪個地方的石頭是被"烹煮"過的石頭？請解釋你的答案。
- Any condiment? / 想要什麼樣的醬來搭配你的石頭？
Please observe the color of the rocks near the fumaroles and the surrounding carefully. Apart from the colors of the "raw" and "cooked" rocks, what other colors do you see? Do you think these rocks have such a color that is caused by the vapor? What mineral elements affect?
請仔細觀察噴氣口附近還有周圍山壁的石頭顏色，除了生的與熟的石頭的顏色外，你還看到什麼顏色的石頭？你覺得這些石頭會有這樣的顏色是受到蒸氣所影響嗎？你覺得有哪些礦物元素影響了石頭的顏色呢？
- Would you like to have some desserts? / 飯後來點點心吧？
Please observe the periphery of the fumaroles carefully, you could see some yellow objects that looks like flowers. It called "yu no hana (湯の花)" by the Japanese in the past, and people in Beitou called them sulfur flowers. Please answer the following questions based on your observation of sulfur flowers.
In your opinions, is the sulfur flower a plant or a mineral? How is the sulfur flower formed? What is its main ingredient?
仔細觀察噴氣口的周邊，你可以看到如同花朵般的黃色物體，這些東西在過去被日本人稱為湯の花，而北投人稱他為磺花，請根據你對磺花的觀察來回答以下問題：
請問你覺得磺花是植物還是礦物？你覺得他是如何形成的？你覺得他的主要成分是什麼？
- Review time / 你是個"美石家"嗎？
Please explain the phenomena, processes and results in the following photo based on what you have learned on this EarthCache. (The photo is taken at the reference point, you could visit there if you want to have a closer look.)
請根據你在這個地質寶上學到的東西來解釋下面這張照片中發生的現象、經過、結果。(這張照片是在reference point所拍攝，如果你想要觀察的更仔細的話，不妨前往看看。)
- Photo time / 用餐完畢別忘了拍張照上傳👍
Take a photo with "the witch’s cauldron" at the posted coordinates, the photos must contain either you (no face required), your personal item, a piece of paper with your geocaching name, or any else that would makes your photos unique.
離開前，當然要和"女巫的大釜" (公佈座標處) 合影留念啊！這樣才夠ROCK！😉
Notes:
- Please don’t post any answers in your log.
- Please send the answers to the owner via message system of geocaching.com. Only the accounts that sent the answers could log as found, so please make sure you sent your own answers even you’re in the group-hunting.
- You MUST visit the earthcache location to claim a find. I’ll delete the logs of people who clearly didn’t visit the earthcache or who didn't complete the logging tasks.
- You don’t have to wait the permission to log after you send the answers. Any logs without all of the answers will be deleted.
REF: 台北地質之旅, wikipedia, britannica.com